---
title: "Raymond Reiter"
type: "entity"
entity_kind: "person"
status: "hub"
canonical_name: "Raymond Reiter"
aliases: ["Ray Reiter","R. Reiter"]
first_seen: "2026-07-12T00:00:00.000Z"
writer_model: "claude-opus-4-8"
connects_to: ["default logic","closed-world assumption","non-monotonic reasoning","knowledge representation","Answer Set Programming"]
seek_code_commit: "a619c8a"
---


Canadian computer scientist (1939–2002), a founder of non-monotonic reasoning in artificial intelligence: he formalized the **closed-world assumption** for incomplete databases (1978) and **default logic** (1980), the machinery for drawing defeasible conclusions from what is *not* known. His work is a standard citation for reasoning that treats unproven statements as false.

Reiter matters to this vault as the AI lineage underneath the logic-programming account of human reasoning: Sakama's ASP formalization of the conditional-reasoning "fallacies" is grounded explicitly in Reiter's default logic ([[claim-conditional-reasoning-fallacies-as-closed-world-inference-in-asp]]). He is also the subject of a small but real finding — [[entity-keith-stenning|Stenning]] and [[entity-michiel-van-lambalgen|van Lambalgen]]'s own 2001/2004 papers reach "[[entity-closed-world-assumption|closed-world reasoning]]" *without* citing Reiter, developing the idea through a linguistics/philosophy-of-language route rather than the AI/database one ([[claim-stenning-van-lambalgen-do-not-use-negation-as-failure-in-2001-2004-papers]]). Two independent routes into the same terminology.

## References
- [[claim-conditional-reasoning-fallacies-as-closed-world-inference-in-asp]] · [[claim-stenning-van-lambalgen-do-not-use-negation-as-failure-in-2001-2004-papers]]
- Captures: 2026-08-31-do-stenning-van-lambalgen-actually-model-the-wason